When animating objects and properties in Blender, Actions record and contain the data. As everything else in Blender, Actions are data-blocks.
So when you animate an object by changing its location with keyframes, the animation is saved to the Action.
Each property has a channel which it is recorded to, for example,
Cube.location.x is recorded to Channel X Location.
The X location and Y location properties can be shared across multiple objects,
if all objects have X location and Y location properties beneath them.
Record and contain animation data.
Are groups of channels.
F-Curves are used to interpolate the difference between the keyframes.
Keyframes are used to set the values of properties bound to a point in time.
Working with Actions
When you first animate an object by adding keyframes, Blender creates an Action to record the data.
If you are making multiple actions for the same object, press the shield button for each action. This will give the actions a Fake User and will make Blender save the unlinked actions.
Objects can only use one Action at a time for editing. The NLA Editor is used to blend multiple actions together.
Object and Pose Modes
The final motion of objects or bones depends not only on the keyframed animation, but also on any active F-curve modifiers, drivers, and constraints. On each frame of all the scene's frames, the Bake Action tool computes the final animation of the selected objects or bones with all those modifiers, drivers, and constraints applied, and keyframes the result.
This can be useful for adding deviation to a cyclic action like a Walk Cycle, or to create a keyframe animation created from drivers or constraints.